Analog television (TV) broadcasting is being replaced by digital TV broadcasting. In order to receive digital broadcast signals, a set-top box is required. The set-top box is designed to receive various digital broadcast channels. The set-top box has CAS information including information on the channels subscribed by a subscriber. The broadcast service provider provides the subscriber with the broadcast service based on the subscription information.
The CAS is a restrictive access system for restricting unauthorized users from accessing the channels or services. The CAS allows only authorized subscribers to descramble the scrambled signals broadcast by the broadcasting company and watch the broadcast. The basic requirements for implementing such a system are program and data scrambling for ensuring security of the communication links and subscriber authentication and access control functions.
FIG. 1 is a block diagram illustrating an exemplary set-top box-based broadcast reception system, according to an embodiment of the present disclosure. In reference to FIG. 1, the broadcast reception system includes a broadcast provider server 110, a set-top box 120, and a TV 130. The TV 130 is connected to the set-top box 120. If a CAS card 125 is inserted into the set-top box 120, then the set-top box 120 decrypts the encrypted signals with the CAS information stored in the CAS card 125. The decrypted signals are modulated into radio frequency (RF) signals and transferred to the TV 130 for viewing by the subscriber.
FIG. 2 is a block diagram illustrating another exemplary set-top box-based broadcast reception system, according to an embodiment of the present disclosure. In reference to FIG. 2, the broadcast reception system includes a broadcast provider server 210, a first set-top box 220, a second set-top box 230, a first TV 240, and a second TV 250. The first TV 240 is connected to the first set-top box 220, and the second TV 250 is connected to the second set-top box 230. Each of the first and second TVs 240 and 250 should be connected to a set-top box to receive digital broadcast signals. The set-top boxes 220 and 230 have CAS cards 225 and 235 respectively inserted therein and decrypt the encrypted signals with the CAS information stored in the respective CAS cards 225 and 235; the decrypted signals are modulated into RF signals and transferred to the first and second TVs 240 and 250 for viewing by the subscriber(s).
As described above, in order to receive digital broadcast signals, a TV should be connected to a set-top box having a physical CAS card inserted therein. However, the legacy set-top box-based broadcast reception systems have drawbacks as they require extra devices in addition to a TV for use of CAS information in receiving broadcast signals and laborious installation processes thereof, resulting in user inconvenience.